Questions from College Physics

Q: A student wants to lose some weight. He knows that rigorous

A student wants to lose some weight. He knows that rigorous aerobic activity uses about 700 kcal/h (2900 kJ/h) and that it takes about 2000 kcal per day (8400 kJ) just to support necessary biological...

Q: (a) What is the entropy change of 1.00

(a) What is the entropy change of 1.00 mol of H2O when it changes from ice to water at 0.0°C? (b) If the ice is in contact with an environment at a temperature of 10.0°C, what is the entropy change of...

Q: A student in a lecture hall has 0.25 m2 of

A student in a lecture hall has 0.25 m2 of skin (arms, hands, and head) exposed. The skin is at 34°C and has an emissivity of 0.97. The temperature of the room is 20°C (air, walls, ceiling, and floor...

Q: A pilot starting from Athens, New York, wishes to fly

A pilot starting from Athens, New York, wishes to fly to Sparta, New York, which is 320 km from Athens in the direction 20.0° north of east. The pilot heads directly for Sparta and flies at an airspee...

Q: Estimate the entropy change of 850 g of water when it is

Estimate the entropy change of 850 g of water when it is heated from 20.0°C to 50.0°C. [Hint: Assume that the heat flows into the water at an average temperature of 35.0°C.]

Q: A manometer using oil (density 0.90 g/cm3

A manometer using oil (density 0.90 g/cm3) as a fluid is connected to an air tank. Suddenly the pressure in the tank increases by 7.4 mmHg. (a) By how much does the fluid level rise in the side of th...

Q: It is often argued that the head is the most important part

It is often argued that the head is the most important part of the body to cover when out in cold weather. Estimate the total energy loss by radiation if a person's head is uncovered for 15 min on a v...

Q: For a more realistic estimate of the maximum coefficient of performance of

For a more realistic estimate of the maximum coefficient of performance of a heat pump, assume that a heat pump takes in heat from the outdoors at 10°C below the ambient outdoor temperature, to accoun...

Q: Consider the net rate of heat loss by radiation from exposed skin

Consider the net rate of heat loss by radiation from exposed skin on a cold day. By what factor does the rate for an outdoor temperature of 0°C exceed the rate at 5°C? Assume an initial skin temperatu...

Q: A container holding 1.20 kg of water at 20.

A container holding 1.20 kg of water at 20.0°C is placed in a freezer that is kept at −20.0°C. The water freezes and comes to thermal equilibrium with the interior of the freezer. What is the minimum...